Mike, what you've got is fine. Put Tritium front sights on both guns, I think there's Tritium rears available for the 66 and I'd suggest one minor change on both guns:
Get a box of Cor-Bon full-house 125grain combat JHPs in 357. Don't shoot any, don't even practice with 'em...just load one each in each gun, set up under the hammer (so it's the last round fired).
This gives you two things:
1) The gun now tells you when it's dry by trying to rip your arm off
.
2) By then, there'll be enough other rounds flying that most possible bystanders have hit the deck and you can throw a "supernasty" with less risk.
3) If the 38s ain't slowed his dumb butt down, said Cor-Bon will get his attention
.
The 38+P you're using now is one of the top three such loads, so stick with it if you dig it ('cept on those last-at-bat rounds).
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NOTE: yes, you could get some sort of 44Mag/Spl sixgun and load mild Magnums or hot Specials and be slightly more effective. BUT: practice costs will go up, and the two guns you have now make for fine street carry pieces, and the caliber is such that practice is cheap. I am a strong proponent of "mastering one or two guns" and using them for everything...in a pinch, you will KNOW and trust that piece.